ACT 2004 Subaru Impreza XACT Flywheel Prolite - 600240

ACT XACT Prolite Flywheel — Subaru STI, 11.8 lb (600240)

ACT's lightest flywheel offering with the lowest inertia, designed for best throttle response and acceleration. At 11.8 lbs it's roughly 8 pounds under the factory unit — a large amount of rotating mass gone from the crank on an AWD chassis.

One-piece construction with an integral ring gear. Less opportunity for failure, uniform heat transfer from the clutch disc, and no warped inserts or loose ring gears. Heat-treated forging for strength and toughness with an induction-hardened ring gear for maximum life. Material is distributed for strength, heat tolerance, and rigidity rather than simply removed.

CNC machined and dynamically computer balanced for smooth high-RPM reliability. Lead-in chamfers, heat treated and tempered.

Preferred for road racing and rally, with reduced drivability. ACT is direct about the trade. Dramatically improved engine response and acceleration, with mild to moderate gear rattle. Less inertia off the line means more throttle from a stop and more deliberate clutch engagement.

Serviceable and resurfaceable like a stock flywheel, no special process and no additional parts needed.

Specs: 11.8 lbs, 124-tooth ring gear, forged steel, SFI 1.1 rated. Internal engine balance. Pilot bearing PB1004 included.

Fitment: 04-21 Subaru WRX STI, manual transmission.

Flywheel bolts not included — OEM Subaru (800610740) or ARP (254-2801). Worth adding ARP hardware while it's apart.